Data Sciences Challenges
Explore data science challenges on Ewance to build skills employers expect from analysts and ML engineers. Work through challenges on data cleaning, exploratory analysis, modeling, and storytelling with data.
Most Popular
- CodeSeniorNew
Build a Lock-Free MPMC Queue for a Trading-Backend Hot Path
Implement Vyukov's bounded MPMC queue in C++20 using atomic operations with explicit memory orderings (relaxed where safe, acquire/release on the enqueue/dequeue handshake). Use…
- Lock Free Algorithms
- Memory Models
- Cpp
Open coursework - CodeIntermediateNew
Apply Software Transactional Memory to a Real-Time Auction Book
Implement two variants of the same auction-book API (best-bid/best-ask lookup, place-order, cancel-order, match-orders): (1) baseline with java.util.concurrent locks + a SkipLis…
- Transactional Memory
- Concurrent Data Structures
- Haskell
Advanced Concurrency and Parallel Computing - DesignIntermediateNew
Design Multi-Tenant Network Policies with Calico Tier Enforcement
Receive the cluster topology (120 customer namespaces + 4 platform namespaces), the application traffic patterns (frontend talks to backend talks to its tenant's database), and …
- Kubernetes
- Network Policy
- Calico
Container Orchestration with Kubernetes - CodeIntermediateNew
Migrate Stateful Workloads to StatefulSets with Storage Class Tuning
Receive the current Redis Sentinel topology (3 nodes, ~120GB data), the EBS gp3 baseline performance requirements (3,000 IOPS, 125 MB/s), and the cluster (EKS 1.29 with the EBS …
- Kubernetes
- Statefulsets
- Storage Classes
Container Orchestration with Kubernetes Develop in-demand professional skills.
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Why Ewance
- AnalysisIntermediateNew
Threat Model a Water-Utility SCADA Network Before a Migration
Review provided network diagrams (current and proposed), the asset inventory (around 180 PLCs (programmable logic controllers), 22 engineering workstations, 6 historian servers)…
- Threat Modeling
- Ics Security
- Scada
Cyber-Physical and Cybercrime Topics - AnalysisSeniorNew
Forensic Reconstruction of an Anonymized Energy-Grid Incident
Treat this as a case file and work timeline-first. From the incident intake record (intake-file), establish the known facts and the 19-minute window. Reconcile the remote-termin…
- Digital Forensics
- Incident Response
- Ics Security
Open coursework - AnalysisIntermediateNew
Mine Basket History to Justify Grocery Shelf-Adjacency Changes
Work only from the materials provided. Use the basket transactions extract to mine frequent itemsets with FP-growth, tuning the minimum support level separately for the food, ho…
- Frequent Itemset Mining
- Fp Growth
- Spark
Open coursework - CodeIntermediateNew
Build a Hybrid Recommendation System for an Indie Streaming Catalog
Use the provided 6-month anonymized event log (around 320M play events, 1.4M unique users in the held-out cohort), audio embeddings (256-d), and track metadata. Implement (1) an…
- Recommendation Systems
- Collaborative Filtering
- Content Based Recommendation
Open coursework - Browse challenges
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Pricing Strategist
Set the price that captures value without leaving sales on the table. Demand modelling, willingness-to-pay research, and the disciplined experimentation that turns pricing into a competitive advantage.
- AnalysisBeginnerNew
Re-segment a SaaS Customer Base by How Accounts Actually Use the Product
Using the provided usage signals dataset, engineer features that capture how deeply and how often accounts use the product (not just raw volume), standardize them, and run at le…
- Clustering
- K Means
- Hdbscan
Open coursework - ResearchBeginnerNew
Research Roadmap for Meridian DSP's Bid-Matching Pipeline
Using the VP of Machine Learning's context memo (vp-brief) and the pipeline case file (pipeline-case-file) to ground every recommendation in Meridian's actual system, assemble a…
- Information Retrieval
- Learning To Rank
- Research Synthesis
Open coursework - CodeFoundationalNew
Swap a List Scan for a Min-Heap in the Dispatcher
Working only from the materials provided, your job is to make the courier-selection logic faster and to show, with evidence, that it actually got faster. First, read the de-iden…
- Heap Data Structure
- Complexity Analysis
- Python
Open coursework - CodeBeginnerNew
Choose a Hash Table or Trie for a URL-Shortener Cache
Build two caches that satisfy the contract in the cache specification (provided): one hash table using linear probing and one compressed trie, both enforcing the same two-millio…
- Hash Tables
- Trie Data Structure
- Benchmarking
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Why Ewance
- AnalysisBeginnerNew
Model Bogotá's Bike-Share Network as a Graph for Overnight Rebalancing
Using only the supplied station directory, the aggregated origin-to-destination trip table, and the operations brief, build a directed weighted graph where each station is a nod…
- Graphs
- Networkx
- Shortest Path
Open coursework - CodeIntermediateNew
Design a Lock-Free Concurrent Queue for an Event Bus
Implement an MPSC (multi-producer single-consumer) ring-buffer queue in Go using atomic operations only — no mutexes. Prove correctness with the Go race detector across 8 produc…
- Concurrent Data Structures
- Lock Free Programming
- Go
Data Structures - CodeIntermediateNew
Index a Reference Genome with a Suffix Array in Rust
Using the reference-genome FASTA in the provided materials, build an in-memory suffix array (DC3 or SA-IS construction) over the 4-letter DNA alphabet in Rust, then implement co…
- Suffix Arrays
- String Algorithms
- Rust
Open coursework - DesignBeginnerNew
Redesign an Executive Revenue Dashboard for an E-Commerce Marketplace
Interview the CFO, the head of category, and 2 finance analysts for 30 minutes each to elicit the 6 analytic tasks the dashboard must support (e.g. month-over-month variance, ca…
- Dashboard Design
- Visual Encoding
- Task Analysis
Information and Data Visualization - DesignIntermediateNew
Design an Interactive Subway On-Time Performance Visualization
Using the provided arrival-performance sample dataset, design a small-multiples layout — one compact panel per subway line — that uses a horizon-chart encoding to show on-time p…
- D3
- Webgl
- Interactive Visualization
Open coursework - ResearchIntermediateNew
Recommend a Color Scale for a Flood-Risk Map With Evidence
Working only from the provided materials, reach and defend a single recommendation. Read the decision file (decision-file) to understand the actors, the prior complaint, and the…
- Perceptual Study
- Color Scales
- Experimental Design
Open coursework - DesignIntermediateNew
Author a Scrollytelling Story on a Three-Week Ad-Fraud Anomaly
Using the internal investigation report (provided) and the anomaly dataset (provided), design a seven-section scrollytelling narrative and build it as a static web page. Structu…
- Narrative Visualization
- Scrollytelling
- Svelte
Open coursework - CodeIntermediateNew
Build a WCAG 2.2 AA Accessible Chart Component Library
Build a React and TypeScript component library that exports four chart components (bar, line, scatter, heatmap), each rendering the figures in the provided sample analytics data…
- Accessibility
- Wcag 2
- React
Open coursework - DesignFoundationalNew
Redesign a Vet-Clinic SaaS Database to Third Normal Form
Using the current schema dump and the eight most-common reporting queries provided to you, design a replacement database structure for VetLedger. First, produce an entity-relati…
- Data Modeling
- Normalization
- SQL
Open coursework - AnalysisBeginnerNew
Index a Slow 90-Million-Row FinTech Reporting Database
Your analysis task is to read the engineering ticket and the six reporting queries in the case file (M1), study the transactions table definition, column statistics, and write w…
- Indexing
- Query Optimization
- Explain Analyze
Open coursework - DesignIntermediateNew
Resolve the Quota Double-Spend: Design Meterly's Order-Provisioning Schema
Working only from the materials provided, reach and defend a database design. Read the de-identified incident record (incident-file) and the business-rules brief (requirements-b…
- Transactions
- Acid
- Isolation Levels
Open coursework - AnalysisBeginnerNew
Plan and Validate a MySQL-to-PostgreSQL Records Migration
Using the de-identified case record (incident-file-records-office), the representative schema export (mysql-schema-sample), and the anonymized staging extract (staging-records-s…
- Database Migration
- Mysql
- Postgresql
Open coursework
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